1. Field of the Invention
The invention relates generally to the field of imaging. More particularly, the invention relates to methods and systems for image reconstruction using cameras, such as Compton cameras.
2. Discussion of the Related Art
In vivo imaging methods, such as Single Positron Emitting Computed Tomography (SPECT), use gamma radio tracers to track biochemical, molecular, and/or physiopathological processes of various human diseases. Further, such imaging methods may provide detection of contaminates in a nuclear facility and nuclear waste sites as well as serve as a defense utility by imaging radiation activity on missiles, planes, etc. Radiation emitted from the target of interest are detected by a gamma ray camera device of the imaging system which forms an image of the target based on the concentration and distribution of the radioactive material, e.g., gamma radio tracers within the target.
Conventional gamma ray cameras usually include a plurality of detectors For example, the Anger camera includes collimators within the detectors to limit radiation trajectories observed by the detector. In addition, conventional gamma cameras are stationary within an imaging system, allowing only one view of the target to be observed. However, conventional cameras are inefficient because the cameras lack the ability to image two or more isotopes at the same time.
Recently, Compton cameras have been integrated into imaging systems as an alternative to the conventional gamma cameras to further enhance and improve upon the quality of images being reconstructed. For example, the Compton camera can detect one to two orders more radiation emissions, such as photons emitted from a target, than a conventional camera. In addition, the Compton camera can readily image a relatively wide range of energies. Generally, Compton cameras include two semiconductor detectors configured in parallel with one another. The first detector may be capable of measuring the radiation emitted from a target, such as a photon emission. In particular, the first detector measures the point in which the photon contacts the first detector as well as the amount of energy lost by the photon when the photon goes through Compton scattering within the detector. As a result of the scatter, the photon travels in a new direction and interacts with the second detector, in which the second detector can measure the point at which the photon contacts the second detector.
Current methods for image reconstruction utilizes the cone projection data collected from the Compton camera and convert the data into plane projection data. Such methods may include using an infinite series expansion to calculate the plane projection data. However, such methods require an a large number of calculations to be performed, and therefore requires a greater number of resources to be utilized and may produce poor quality images.
The referenced shortcomings are not intended to be exhaustive, but rather are among many that tend to impair the effectiveness of previously known techniques concerning image reconstruction however, those mentioned here are sufficient to demonstrate that methodology appearing in the art have not been altogether satisfactory and that a significant need exists for the techniques described and claimed in this disclosure.